future technology magazine · 2013-07-19 · future technology magazine issue 1303 design note:...

F U T U R E T E C H N O L O G Y M A G A Z I N E

I S S U E 1 3 0 3

Design Note: page 13Sensor reference design solves analogue signal-chain and microcontroller-integration challenges

Technical View: pages 20-23 How a real-time operating system can benefit your application, and how to choose wisely

Application Spotlight: pages 14-18New ambient-light sensor from Rohm adds power-management capability

Component Focus: pages 2-12 Freescale Kinetis MCUs bring ARM® Cortex™-M4power to cost-sensitive applications

In association with www.my-boardclub.com

Murata to integrate NEC’s magneto-resistancesensor businessMurata and NEC have agreed to transfer NEC’sMagneto-Resistance (MR) sensor business toMurata. Murata will integrate the technologyassets and expertise of NEC’s MR sensorbusiness with its own technologies and customerbase. The transfer, which is scheduled to becompleted by June 1, 2013, enables Murata toreinforce its initiatives in the expanding MR-sensor segment of the consumer-products andindustrial-equipment markets.

NEC’s MR sensors are used for tasks suchas open/close detection in mobile phones orlaptop PCs and detecting volumes of fluids inwater heaters, water meters and gas meters.Murata has a large magnetic-sensors portfolioincluding currency-identification sensors androtation sensors, and is also pursuing newmagnetic-sensing technologies to expand itsbusiness in the industrial-equipment, automotiveand consumer-products segments.

Flip-chip LEDs from Philips Lumileds boostdesign flexibilityNew LUXEON® Flip-Chip LED devices fromPhilips Lumileds will enable the next generationof lighting applications by enhancing designflexibility. The company says adding theselatest devices to its portfolio gives luminairemanufacturers the choice of incorporatingpackaged LEDs as they have in the past, orstarting with the LED die and customising thephosphor and packaging to best suit theirlighting application.

While traditional wire bonding limits thepacking and power density of LEDs, LUXEONFlip-Chip LEDs can be packaged closer andcan be driven at a higher current density. Thisrequires fewer emitters to achieve a higherlumen output at higher lumen densities. Thiscapability is especially advantageous with chip-on-board and other high-power applications.

ON Semiconductor’s video-processor ICs forsmall LCD panelsON Semiconductor has released two highlyintegrated image-signal processor ICs forapplications using small LCD screens, such asautomotive reversing cameras and consumervideo-monitoring security systems. TheLC749000PT for automotive applications andthe LC749000AT for consumer productsprovide built-in features to optimise the displayedimage, such as automatic scaling of video outputto the correct display resolution and built-incalibration for smoother gradients. A built-inOn-Screen Display (OSD) function allows textcharacters to be superimposed on the picturedata, while an OSD switch allows use of anexternal graphics IC for more advanced graphicaloverlays. Both devices support screen resolutionsup to Wide Video Graphics Array (WVGA).

S TA R P R O D U C T

2 E M A I L I N F O @ M Y- F T M . C O M F O R S A M P L E S A N D D ATA S H E E T S

The FAN6224, the firsthigh- and low-side SRcontroller in Fairchild’smWSaver™ technologyseries, offers a GreenMode operating statewhich the deviceautomatically adopts underlight loads. In Green-Modeoperation, SR-switchingoperations are stoppedand large parts of thecircuit are shut down. As aresult, operating currentfalls to 300µA.

The conditions thattrigger the device to enterand exit Green-Mode areadjustable within a certainrange through theselection of an externalresistor connected to theProgrammable (RP) pin.

The implementation of a technique forachieving low power consumption in light-loador stand-by conditions will help manufacturersof consumer electronics devices to meet thelatest power-efficiency regulations, which setnew low limits for stand-by power consumption.To date, SR controllers have been widely usedto achieve high efficiency in AC/DC powersupplies at full load, but at the cost of highstand-by power consumption as well as designcomplexity.

The FAN6224 allows system designers toenjoy the benefits of high full-load efficiency innormal operation and to disable large power-consuming elements of the chip at light loads,such as when the host device is in stand-by.

Using a linear-predict timing-controltechnique, this new SR controller employs asimple control method with no current-sensecircuitry, an approach that provides for highnoise immunity. This makes the chip ideallysuited to high- and low-side flyback convertersin continuous or discontinuous conductionmode and to quasi-resonant systems.

The FAN6224 also provides PWM frequencytracking and detects the secondary-sidewinding voltage. It is able to operate in bothfixed- and variable-frequency systems atup to 140kHz.

FAIRCHILD SEMICONDUCTOR

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©Copyright 2013 Future Electronics Ltd. All trademarks contained herein arethe property of their respective owners. Applications for product samples,badge boards, demonstration boards, Future-Blox Boards and otheradvertised materials from Future Electronics are subject to qualification.

Newsin brief

Fairchild Semiconductor hasintroduced the FAN6224, a secondary-side Synchronous Rectification (SR)controller which provides high systemefficiency in AC/DCpower suppliesoperating in bothnormal and stand-byconditions.

AC-DC converter controlleroffers high efficiency at fulland light loads


APPLICATIONS• AC-DC power supplies• Open-frame switched-mode power

supplies

FEATURES• 12V gate-driver clamp• Suitable for forward freewheeling

rectification• Over-voltage protection • Open/short protection on Winding-

protection, Programmable and Reset-control pins

• Over-temperature protection

ENERGY MEDICAL LIGHTING INDUSTRY SECURITY AUTOMOTIVE

Fairchild’s FDB9403: page 7Vishay’s 160 CLA: page 11 PARTNERWORKING

3V I S I T T H E O N L I N E F T M M A G A Z I N E AT: W WW . M Y- F T M . C O M

C O M P O N E N T F O C U S

Automotive MCUs enhance securityand connectivity for body control

Secure Qorivva processors for automotive applications provide a choice of single-core or dual-core architecture

Integrated peripherals support popular automotive connectivitystandards

FREESCALE

Rugged MOSFETs in dual power packageshrink next-generation automotive modules

NXP Semiconductors’ BUK7K6R8-40Eenables the next step in miniaturisingelectronic modules such as automotiveElectronic Control Units (ECUs) byintegrating two N-channel TrenchMOSstandard-level MOSFETs in aLFPAK56D (dual Power-S08) package.

Designed and qualified to AEC-Q101, theBUK7K6R8-40E has repetitive avalancherating and devices are 100% avalanche testedto withstand typical automotive electricalhazards such as load dump and batterydisconnection. The maximum rated junctiontemperature of 175°C also allows use in harshthermal conditions.

The LFPAK56D package contributes to the

NXP SEMICONDUCTORS

Freescale Qorivva MPC564xB/C 32-bitmicrocontrollers combine the convenienceof Power Architecture® computing withextended features for automotive Body-Control Module (BCM) applications andare the first devices to feature aCryptographic-Services Engine (CSE)meeting the Secure Hardware Encryption(SHE) specification.

The CSE provides cryptographic hardwarefeatures that allow secure and trustedcommunications. Unlike alternative devices thatsupport security through software algorithms,Qorivva MPC564xB/C MCUs with CSE areable to control cryptographic keys in thehardware domain. This significantly lowerssecurity risks, reduces CPU loading andincreases encryption/decryption performance.

In addition, MPC564xB/C MCUs arefeatured to meet growing demands from OEMand Tier-1 BCM producers with enhancedfeature sets and increased memory space.

With up to 3Mbyte of Flash and 256kbyte ofRAM, they provide among the highest MCUmemory density in the market. The high RAMdensity can handle message buffering fornumerous communications peripheralsinterfacing to a large number of body-electronicsnodes. The 256kbyte RAM also supports therequirements of AUTOSAR-based softwaremodules, which require higher quantities of RAM.

Enhanced communication capabilitiesenable BCMs to connect to the increasingamount of electronics featured in today’s

APPLICATIONS• High-end Body-Control Modules (BCM)• Automotive gateway controllers

FEATURES• Crossbar-switch architecture• eMIOS timer combining multiple counter

sources• Cross-triggering unit• Multiple analogue peripherals and

PWM/timers• Low-power modes down to 25µA• Pin and software compatibility with

MPC560xB/C family



APPLICATIONS• Engine and transmission controllers• Braking-solenoid and motor drives• Lamp control• Start-stop micro-hybrid applications• Ultra high-performance power switching• General-purpose automotive switching

where space is at a premium

FEATURES• 40V maximum drain-source voltage• 5.8mΩ typical on-state resistance @

VGS = 10V, 25°C• True standard-level gate with VGS(th)

>1V @ 175°C• 9.1nC typical gate-drain charge



Part Number Core(s) Flash RAM CSE FlexRay Ethernet LINFlex SPI FlexCAN

MPC5646C e200z4 + e200z0 3MB 256kb

Optional Yes

Yes

10 8 6

MPC5646B e200z4 3MB 192kb NoMPC5645C e200z4 + e200z0 2MB 256kb YesMPC5645B e200z4 2MB 160kb NoMPC5644C e200z4 + e200z0 1.5MB 192kb YesMPC5644B e200z4 1.5MB 128kb No

high-temperature capability of the BUK7K6R8-40E, as its wirebond-free copper-clip internal structure lowers thermal resistance.A FloTHERM® thermal model for theBUK7K6R8-40E is available to help designersto optimise the thermal design of their systems.

In addition, very low package inductanceand ohmic resistance help boost efficiency andenable each MOSFET to sustain a continuousdrain current of up to 40A.

The LFPAK56D package also allowsextremely space-efficient circuit implementationcompared to earlier single MOSFETs inLFPAK56 or DPAK packages. Using oneBUK7K6R8-40E, two MOSFETs can beimplemented in a pc-board footprint of 31mm2

compared to 62mm2 or 140mm2 needed fortwo LFPAK or DPAK devices, respectively.Despite this advantage, the LFPAK56D isfootprint compatible with other Power-S08packages, thereby simplifying design-in tonext-generation automotive modules.

vehicles. These include Ethernet and FlexRay™

controllers supporting high-speed Flashprogramming, vehicle diagnostics andsafety/chassis network interfacing. In particular,a FlexCAN module supporting both FIFO andmailbox data storage for use in CANgateways, and a LINFlex module that providesfully automated LIN-message management toreduce CPU loading and message latencies.

Designers using this microcontroller familycan also choose from a single PowerArchitecture e200z4d core or dual-corevariants featuring an additional e200z0h coreto meet their system-performance targets. Theasymmetric dual-core architecture hasadvanced power management that allows themore powerful e200z4d core to be put intoenergy-saving sleep mode while the e200z0hcontinues performing background functions.

Integrated 50MBd industrial fibre receiver reducescomponent count by 80%



AVAGO TECHNOLOGIES fibre-optic receivers to support customersmigrating from traditional 5MBd opticalnetworks, which are no longer fast enough foruse in sub-station automation and smart-gridapplications. As more control equipment isconnected to the network, higher-bandwidthcomponents are required to provide reliableand safe transmission of more data traffic.

To implement a complete 50MBd network,the AFBR-24x9xZ receivers may be paired

with Avago fibre-optictransmitters, the HFBR-14xxZ (820nm LED) andHFBR-1712TZ (850nmVCSEL), providing linkdistances of up to 3km at20MBd on multimode glass-fibre-optic cable, and up to1km at 50MBd.

The AFBR-24x9xZ devices arecompatible with industry-standard

ST and SMA connectors. Theyoperate at data rates from 100kBd up

to 50MBd, and support 10Base-FLnetworks.

APPLICATIONS• Industrial control and factory automation• High-voltage isolation• Elimination of ground loops• Power sub-station automation

FEATURES• High immunity to noise and EMI• Received-Signal Strength Indicator (RSSI)• Compatible with 10Base-FL standard• 3.3V or 5V supply voltage • Operating temperature range:

-40°C to 85°C



Part Number Description

AFBR-2409Z Receiver with SMA portAFBR-2419Z Receiver with ST portAFBR-2419TZ Receiver with threaded ST portAFBR-2419MZ Receiver with metal ST port

The AFBR-24x9xZreceivers use state-of-the-art technologyto integrate aphotodiode with adigitiser IC on the samesilicon chip. By using thenew Avago receiver instead ofexisting discrete solutions, thedesigner can eliminate one externalIC and 18 discrete components froma 50MBd receiver circuit.

Avago has introduced the new integrated

Avago Technologies has released afamily of 50MBd, 820nm integratedfibre-optic receivers that let designersimplement a simpler circuit using far fewer components.

Integrated power module for compact Class-Daudio amplifier

Slim, thermally efficient packages and high integration enable designers to createcompact new audio designs

International Rectifier has expanded itsPowIRaudio™ family of integratedpower modules with theintroduction of the IR4311M andIR4312M. These 40V powermodules offer a compact meansto implement a low-power Class-Daudio amplifier with no heatsink.

They combine an advanced audio-controller IC with MOSFETs optimisedfor audio performance, offering highefficiency, low distortion and low EMI.Total harmonic distortion and noise israted at a typical 0.02% at 1kHz and1W output into a 4Ω load.

The high voltage rating and high noise immunityof the controller IC ensure reliable operation ina wide variety of environmental conditions.

Two reference designs are also available toprovide the design engineer with a guide toimplementing a complete Class-D audioamplifier: the IRAUDAMP15 features theIR4311M and the IRAUDAMP18 features theIR4312M.

INTERNATIONAL RECTIFIERThe devices also offer high peak power output of35W into a 4Ω load in a half-bridge topology.

The IR431xM family can operate without amechanical heatsink over a wide power-supplyrange on either a single or split power supply.

APPLICATIONS• Table-top audio systems • Active speakers • Musical instruments with integrated

amplifiers

FEATURES• Over-current protection• Thermal shut-down• Internal/external shut-down • Floating differential input • Clip detection (IR4312M only)



Part Number Number ofChannels Power Supply Voltage Peak Output Power

(rms per channel) Package

IR4311MPbF 1 40V or +/- 20V 35W PQFN 5mm x 6mm

IR4312MPbF 2 40V or +/- 20V 35W PQFN 7mm x 7mm

EVALUATIONBOARDS AT my-boardclub.com/ftm


Complementary NPN and PNP 40V transistors in world’ssmallest discrete-transistor package

NXP SEMICONDUCTORS

FREESCALE

Freescale has expanded its ARM®

Cortex™-M4 Kinetis microcontrollerportfolio by adding 34 variants in theK11, K12, K21 and K22 sub-familiesoptimised for cost-sensitiveapplications requiring low power andhigh processing efficiency withoptional tamper-detection and securityfeatures.

The latest K11 and K12 microcontrollers, at50MHz and 100MHz, provide a highly featuredentry level into theKinetis portfolio,offering from128kbyte to 1Mbyteof high-speed Flashand 64kbyte ofFlexRAM. They haveup to 11 energy-saving modes with alow-power timer andclock gating toperipherals, multipletimers includingFlexTimers withhardware deadtimeinsertion andquadrature decodingfor motor control, upto 16 DMA channels

for boosting throughput and reducing CPUloading, and connectivity peripherals includingup to three UARTs, an Inter-IC Sound (I2S)serial interface for audio-system interfacing, aSerial Peripheral Interface Master/Slave (DSPI),and an I2C port.

In addition to these features, new K21 andK22 devices add support for Full-speed andHigh-speed USB2.0 On-The-Go with devicecharger-detect capability.

K11 and K21 variants can also be specifiedwith security and tamper-detection features.These include a hardware Cryptographic-Acceleration Unit (CAU) which enables securedata transfer and storage at higher speedsthan software implementations with minimalCPU loading.


APPLICATIONS• General-purpose switching and

amplification• Mobile applications

FEATURES• 120mV VCEsat (IC = 50mA, IB = 5mA)• 300MHz transition frequency• 5dB noise figure• 40V maximum VCE, 200mA maximum IC

(PMBT3904MB)• -40V maximum VCE, -200mA maximum IC

(PMBT3906MB)



APPLICATIONS• Kiosks• Utility meters• Point-of-sale terminals• Medical devices• Remote controls

FEATURES• Cyclic Redundancy Check (CRC) module• 4µs wake-up from stop mode• Full memory and analogue operation

down to 1.71V• 4-channel 32-bit periodic interrupt timer

for RTOS scheduling or trigger source• Carrier-modulator timer for infrared remote

controls



The CAU supports well-known securityalgorithms such as DES, 3DES, AES, MD5,SHA-1 and SHA-256. There is also aRandom-Number Generator (RNG) andhardware tamper-detection unit allowingsecure-key storage with an internal/externaltamper detect capable of alerting the systemto unsecure Flash, temperature/clock/supply-voltage variations and physical attack.

Family Sub-Family

Floating-Point UnitCore Frequency Memory Features

K12 K12D No50MHz

128kbyte to512kbyte General purpose

K12 K12F Yes100MHz

512kbyte to1Mbyte General purpose

K11 K11D No50MHz

128kbyte to512kbyte

Encryption, tamperdetection

K11 K11F Yes100MHz

512kbyte to1Mbyte

Encryption, tamperdetection

K22 K22D No50MHz

128kbyte to512kbyte USB

K22 K22F Yes100MHz

512kbyte to1Mbyte USB

K21 K21D No50MHz

128jbyte to512kbyte

USB, encryption,tamper detection

K21 K21F Yes100MHz

512kbyte to1Mbyte

USB, encryption,tamper detection

The NXP SemiconductorsPMBT3904MB and PMBT3906MB arecomplementary NPN and PNP 40V200mA general-purpose switchingtransistors in the world’s smallestdiscrete-transistor packagedelivering high thermalperformance and ultimateminiaturisation for space-constrained applications.

The DFN1006B-3 (SOT883B)Surface-Mounted Device(SMD) plastic package has anultra-small outline of 1.0mm x0.6mm and height of just

0.37mm, thereby saving board space and alsoallowing use in ultra-thin end-products such ashandheld devices.

The PMBT3904MB and PMBT3906MB havetypical DC current gain (hFE) of 180 at 1V or -1V

collector-emitter voltage,and 10mA or -10mA

collector current,respectively. Thedevices are AEC-Q101 qualified,allowing designers totake advantage of thespace-saving package

dimensions and closelymatched electrical

parameters in a wide rangeof automotive applications.

High-efficiency DSP-enhanced microcontrollers addpowerful security features

Tantalum chip capacitors provide industry’s highestCV rating for space-constrained applications


MICROTAN tantalum chip capacitors are accurate and robust to fulfill demanding applications in harshenvironments

Vishay TL8 MICROTAN® solid tantalum chip capacitors are low-profile and space-efficient devices that deliver the industry’s highest Capacitance-Voltage (CV)rating for enhanced performance in bulk capacitance, energy storage, filtering ordecoupling applications.


These high-performancecapacitors are available insurface-mount chippackages with heights of0.8mm, 0.9mm or 1.0mm,and hence can be used ina wide range of battery-operated handhelds andother space-constrainedapplications.

The packages alsofeature L-shapedterminations, whichdeliver superior solder-joint strength and allowaccurate AutomaticOptical Inspection (AOI)after reflow.

VISHAY

USB-based starter kits speed up a test-drive withleading automotive MCUs microcontrollers. The development board can

operate as a standalone debug tool or can beconnected to the modular Tower Systemdevelopment platform. S12G MCUs are suitedfor automotive body electronics requiring CANor LIN/SAE J2602 communication.

FREESCALE

The TL8 series covers the capacitance rangefrom 3.3µF to 220µF, with devices in EIAstandard 0805, A-case or B-case footprintsand seven voltage ratings from 4V to 35V.

APPLICATIONS• Consumer electronics• Battery operated handhelds• Industrial controls

FEATURES• Operating-temperature range:

-55°C to 125°C• Capacitance tolerance: ±10% or ±20%



APPLICATIONS• Evaluation of microcontrollers for:

• Central gateways• Door, window and seat controls• Body-control modules• HVAC controllers• Lighting controls

FEATURES• On-board microcontrollers• Basic sensors and indicators• Pushbuttons• OSBDM debugger over USB• Plug-in connection to Tower System




DETAILSON PAGE

19

Freescale is assisting rapid prototypingand microcontroller evaluation forimportant automotive microcontrollerfamilies with its emerging series ofStarterTRAK USB development systemsthat provide everything needed to test-drive the microcontroller in a compact,USB-pluggable unit.

StarterTRAK developmentsystems currentlyavailable support the32-bit MPC5606Band MPC5643, andthe 16-bit S12Gfamily.

The TRK-MPC5606B is populated with a32-bit MPC5606B Qorivva microcontroller, andalso features two bi-colour LEDs, two pushbuttons and a temperature sensor. The boardalso contains a PCI card-edge which offersintegration into the Freescale Tower System toconfigure a custom development system ifrequired to meet special design needs. TheMPC5606B microcontroller, built on Power

Architecture® technology, features advancedintegration for body-electronics applications,providing up to 1.5Mbyte Flash and 96kbyteRAM, multi-channel 10-bit and 12-bit ADCs,up to six CAN controllers and up to 10 LINFlexmodules.

The TRK-USB-MPC5643L enables fast andinexpensive design starts using the QorivvaMPC5643L, the first microcontroller to achieveISO 26262 functional-safety standardcertification. Designed specifically to addressISO 26262 up to the requirements of the most

stringent ASIL-D level,the MPC5643Lreduces designcomplexity andcomponent count bycombining keyfunctional safetyfeatures on a singlechip featuring a dual-

core, dual-issue architecture that can bestatically switched between a lock-step modewith redundant processing and a decoupledparallel mode with independently operatingcores.

The third StarterTRAK development systemfor Freescale’s automotive microcontrollers isthe TRK-USB-S12G for low-cost, high-performance and low pin-count S12G 16-bit


MOSFET with low on-resistance boostssystem efficiency

Enhanced efficiency enhances a wide range of automotive body-electronics andpower-train applications


Latest-generation Schottky barrier rectifiers boostpower and temperature capabilities

NXP SEMICONDUCTORS

NXP Semiconductors has extended itsplanar Maximum-Efficiency General-Application (MEGA) Schottky barrierrectifier portfolio by adding fivedevices with high forward-current andreverse-voltage ratings, and maximumjunction temperature of 175°C, for usein high-power applications or harshenvironments.

Fairchild Semiconductor hasreleased a 40V N-channelPowerTrench® MOSFET thatoffers high efficiency andimproved power control inautomotive applications suchas power steering systems.

Benefitting from Fairchild'sshielded-gate technology, theFDB9403 offers lower resistanceand capacitance than previousgenerations of 40V MOSFETs. Infact its on-resistance is 20% lowerthan that of its closest competitors.Combined with low gate-chargevalues across the device’sspecified operating conditions, theimprovements in the FDB9403markedly reduce power dissipationand so help designers to achievehigher system efficiency.

The FDB9403 MOSFET is rated for amaximum drain-source voltage of 40V, and fora continuous current of up to 110A, at a casetemperature of 25°C. Featuring a wide

operating temperature range of -55°C to175°C, it is ideally suited for use in electricalpower steering, suspension control andpower-train management.

The PMEG4010,PMEG6010, PMEG6020and PMEG6030 rectifiershave low forward voltagewhich helps to minimisepower dissipation, and arehoused in FlatPowersurface-mount plasticpackages featuring clip-bond technologysupporting high current andtemperature capabilities.The packages also have

compact dimensions thereby saving space onthe PCB. The SOD123W package of 1A and2A rectifiers measures only 2.6mm x 1.7mm,while 2A and 3A variants in the SOD128package have an outline of 3.8mm x 2.5mm.Both package types have a low profile of1.0mm, allowing use in ultra-slim enclosures.All types are AEC-Q101 qualified.

These devices are ideal for the high-temperature environments of automotive orindustrial applications, and also for poweradapters and other consumer, computing andcommunication applications.


APPLICATIONS• Automotive engine control• Power-train management• Solenoid and motor drivers• Electronic steering• Integrated starter/alternator• Distributed power systems• Primary switch for 12V systems

FEATURES• 1mΩ on-resistance at 10V, 80A• 164nC gate-charge at 10V, 80A • Unclamped inductive switching capability• AEC-Q101 qualified• 0.45°C/W junction-to-case thermal

resistance



APPLICATIONS• Low-voltage rectification• High-efficiency DC/DC converters• Switched-mode power supplies• Reverse-polarity protection

FEATURES• Low forward voltage• Low reverse current• AEC-Q101 qualified• Integrated stress-protection guard ring


Part Number ReverseVoltage

AverageForwardCurrent

MaximumForwardVoltage

MaximumReverseCurrent

Package

PMEG4010ETR 40V 1A 490mV 50µA SOD123W



PMEG6020ETP 60V 2A 530mV 150µA SOD128

PMEG6030ETP 60V 3A 530mV 200µA SOD128

Fairchild’s FAN6224: page 2Vishay’s 160 CLA: page 11 PARTNERWORKING

NXP’s TEA1755: page 10NXP’s PMPB40SNA: page 12 PARTNERWORKING

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Robust FPC connector supports data ratesup to 5Gbits/s


The FH55 series for advanced multimedia and computing applications is easy to install andextremely reliable

Hirose has introduced the FH55 seriesof Flat Printed Circuit (FPC)connectors suitable for USB3.0, PCIExpress® Gen2, Serial ATA Gen3 andHDMI 1.4a designs operating at datarates up to 5Gbits/s.


The innovative design of the impedance-controlled contacts is ideally suited to high-speed communications systems. The signalcontact shape has a flat structure instead ofthe conventional tuning-fork shape. Thisprovides a straight signal path and stops anysignal reflection. The ground contacts areplaced between the differential-pair signalcontacts to reduce crosstalk.

Insertion of the FPC into the actuator iseasy, since it has a wideopening of 115°. A clear tactileclick from the actuator confirmsthat the FPC has lockedcorrectly in the connector.

Side catches in the internalstructure of the connectorlocate and hold a tabbed FPCin place. This enables atemporary holding position forthe FPC, facilitating accurateguided positioning. Furthermorethis increases the retentionforce of the FPC to theconnector, providing a stableand reliable connection.

HIROSESolder wicking is prevented by a special nickelbarrier applied to the contacts. A flux path andsolder pot on the bottom face of theconnector absorb excess flux and solder.

APPLICATIONS• Portable medical devices• Car audio systems• Satellite navigation equipment • LCD displays

FEATURES• 40 contact positions• 0.5A current rating• 0.5mm pitch• High contact reliability• 50V rating



APPLICATIONS• Process control • Machine automation • Factory automation • Control valves and control units• Stand-alone or remote power units• Railway controls

FEATURES• Withstands 25g shock• 1.5kV AC isolation• Rated for 50 mating/un-mating cycles• Complies with ISO/IEC11801 (Cat5e fast

Ethernet), DIN EN 61984, IEEE 61508


Connector carries Ethernet signalsand 10A power in a single housing

TE Connectivity’s Power4Net hybridconnector provides eight power and foursignal contacts in a single, robusthousing suitable for use in machine-automation equipment that requires ahigh-performance data connection andpower of up to 10A.

By combining the power supply and signallines into a single connector, equipmentmanufacturers benefit from a more flexiblemachine architecture. Manufacturers ofmoulding machines, for example, can offerfaster mould-change times by using a

contact points, meets the demandingdurability requirements of real-time Ethernetapplications in industrial automation. A turningcatch-lock ensures safe locking even whenapplied under the effect of vibration or shock. Variants of the Power4Net product are availablewith gold-, silver- or tin-plated contacts. Thedevice supports both wire-to-board and wire-to-wire designs. Featuring radial sealingelements, the Power4Net carries an IP67 rating.

The Power4Net family of connectorscomplies with the Versatile AutomationRandom Access Network (VARAN) standard,an Industrial Ethernet protocol used in factoryautomation.

TE CONNECTIVITY Power4Net connector. The simpler cablingprovided by Power4Net can also reduceinstallation time by as much as 50%. Therobust contact design, incorporating astainless-steel locking lance and multiple

Part Number Description

1103433-1 HC26.Base Housing1103436-1 HC26.Base Housing-metal1108846-1 HC26.Base Housing-PCB1103427-1 HC26.Bu.4.C.4,41103429-1 HC26.Bu.8.C1103432-1 HC26.Bu.12.C1103434-1 HC26.Connector Housing1103440-1 HC26.Connector Housing 180-metal1103467-1 HC26.Connector Housing 180-plastic1103437-1 HC26.Connector Housing-metal1103439-1 HC26.Coupling Housing 180-metal1103470-1 HC26.Coupling Housing 180-plastic1103430-1 HC26.Sti short1103426-1 HC26.Sti.4.C1103428-1 HC26.Sti.8.C1103431-1 HC26.Sti.12.C1103519-1 Set HC26.Accessory1103519-2 Set HC26.Accessory1103483-1 Set HC26.Accessory 1801103483-2 Set HC26.Accessory 180 my-ftm.com/130314FOR PARTS AND

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P.I.E.S E C T I O N


New transceiver offers huge boost to range ofISM band radios

Semtech's latest RF transceivers can operate over distances of more than 8km inpower-conscious applications

SEMTECH

Mid-voltage Dual Cool MOSFETsoffer excellent thermal performance

The FDMS series delivers leading performance and efficiency in the40V to 100V range


Fairchild Semiconductor has expandedits family of MOSFETs featuring DualCool™ packaging technology with arange of mid-voltage devices offeringhigh power density and low thermalresistance.

The SX1272 and SX1273 transceiversfrom Semtech offer dramatically longerrange and lower power consumptionthan competing ISM-band devicesalready on the market.

Using the patented LoRa™ modulationtechnique, the new devices canachieve sensitivity of -138.5dBm. Inaddition, the parts include anintegrated +20dBm power amplifier.Combining extremely high sensitivitywith a high output power createsan impressively high link budget,and makes the SX1272 andSX1273 ideal for applicationsrequiring long range. Semtech saysthat a range of longer than 8km inan urban environment is possible atan output power of +13dBm.

Designers using these parts cantherefore gain valuable benefits

such as elimination of repeaters, lowerinfrastructure costs, longer battery run-timesand higher network capacity. Circuits using theSX1272 and SX1273 can be implemented witha low-cost crystal and bill of materials.

The LoRa modulation technique alsoprovides markedly better blocking andselectivity than FSK modulation. But theSX1272 and SX1273 do support othermodulation schemes including FSK, GFSK,MSK, GMSK and OOK. This makes thedevices suitable for use with WMBus, IEEE 802.15.4g and legacy radio systems.

The new FDMS series of synchronousrectifying PowerTrench® MOSFETs coversvoltage ratings from 40V to 100V, and isintended for use in DC/DC conversionapplications that require excellent switchingperformance and low thermal resistance.

The Dual Cool technology used in the newdevices is an enhanced PQFN package whichenables additional power dissipation throughthe top of the package, resulting in more thana 60% higher power dissipation capability thanstandard PQFN packaging when a heat-sink ismounted.

In the new FDMS mid-voltage series,improvements to the silicon technology andthe Dual Cool package are combined toprovide excellent switching performance as

well as low junction-to-ambient thermalresistance, some four times less than that ofdevices packaged in the standard over-moulded 5mm x 6mm MLP.

The devices in the new mid-voltage FDMSseries are the 40V FDMS8320LDC, the 60VFDMS86500DC, the 80V FDMS86300DC andthe 100V FDMS86101DC. The 40V device israted for a maximum continuous current of130A at a case temperature of 25°C.


APPLICATIONS• ORing FET• Load switching• Synchronous rectification• DC/DC conversion

FEATURES• Maximum on-resistance: FDMS8320LDC (40V)• 1.1mΩ at 10V, 44A• 1.5mΩ at 4.5V, 37AFDMS86500DC (60V)• 2.3mΩ at 10V, 29A• 3.3mΩ at 8V, 24AFDMS86300DC (80V)• 3.1mΩ at 10V, 24A• 4.0mΩ at 8V, 21AFDMS86101DC (100V)• 7.5mΩ at 10V, 14.5A• 12mΩ at 6V, 11.5A



APPLICATIONS• Automated meter reading• Home and building automation• Wireless alarm and security systems• Industrial monitoring and control systems

FEATURES• 158dB maximum link budget• Programmable bit rate up to 300kbits/s• 100dB blocking immunity• Fully integrated synthesiser with a

resolution of 61Hz• Built-in bit synchroniser for clock recovery• Temperature sensor • Low-battery indicator



Typical gate charge is 121nC at up to 10Vgate-source voltage. The current rating of the100V FDMS86101DC is 60A, and typical gatecharge is 31nC.

The SX1272 and SX1273 cover frequenciesfrom 860MHz to 1,050MHz. Semtech willintroduce another device later in 2013 tosupport other sub-1GHz frequency bands.

Latest high-efficiency SMPS controllers enhance energysavings across load range



NXP SEMICONDUCTORS

PROFIBUS reference platform leverages high-performance communication processors

Freescale’s PROFIBUS referenceplatform combines the TWR-P1025Tower System module based on theP1025 QorIQ processor and the TWR-IND-IO connectivity module, acceleratingdevelopment of electronic controlsystems, safety systems and M2Mdevices for remote control andmonitoring in industrial automation.

As industrial automationis transformed by thedesires of variousstakeholders toincrease safety whilealso improving energy,cost efficiency andincreasing productivity,demand for PROFIBUSconnectivity continuesto increase. WhileIndustrial Ethernetbegins penetrating applications such asfactory automation, transportation, energyinfrastructure and building control, PROFIBUSremains the world’s most successful fieldbustechnology. Currently there are over 35 millioninstalled nodes worldwide.

QorIQ processors can also providesimultaneous support for other IndustrialEthernet protocols like PROFINET, EtherCAT®

and EtherNet/IP™.

FREESCALE


DETAILSON PAGE

19

The PROFIBUS reference platform isFreescale’s latest development kit takingadvantage of the TWR-P1025 QorIQ P1 TowerSystem Module for faster development ofadvanced industrial control and connectivity.Other kits utilising this module include theEtherCAT Programmable Logic Controller(PLC) reference platform and the Metro AreaNetwork development kit.

By implementing PROFIBUS Layer 2 on theversatile and proven QUICC-Engine co-processor integrated in the QorIQ P1025, thismodule eliminates the need for a costlyPROFIBUS ASIC and almost completely frees

the processor coresfor applicationprocessing. Thisallows the PROFIBUSprotocol and thecustomer’s controlapplication to runsimultaneously onone chip.

With theintroduction of thismodule, Freescalenow supportsPROFIBUS Master

and Slave on QorIQ and PowerQUICC®

processors with QUICC-Engine technology.The PROFIBUS software can be evaluatedrunning on the TWR-P1025 processor module,and can be accessed viawww.freescale.com/profibusQorIQ.

APPLICATIONS• Industrial power supplies up to 250W• LED-TV adapters• Notebook adapters

FEATURES• On-chip start-up current source• IC power-down feature• Continuous-mode protection using

demagnetization detection • Accurate over-voltage protection for both

converters • Over-power protection independent of

mains voltage • Open control-loop protection for both

converters • General-purpose input for latched

protection



APPLICATIONS• PROFIBUS connectivity• Programmable Logic Controllers (PLCs)• Fieldbus-to-Ethernet gateways• Input/output control

FEATURES• 12Mbit/s transmission rate, certified by

ComDeC• Commercial PROFIBUS slave stack

available• Completed solution deployable on:

• P1012, P1021, P1016 and P1025QorIQ P1 processors

• MPC8309 PowerQUICC processor• TWR-IND-IO connectivity:

RS-232, RS-485, CAN, USB, ADC, DAC



The TEA1755 GreenChip™ III SMPS-controller IC from NXP Semiconductorshas several operating modes foroptimum energy efficiency at all powerlevels, and features an innovative PFC-switching technique that eliminatesvalley hopping.

At high power levels the TEA1755 flybackcontroller operates in Quasi-Resonant (QR)mode or Discontinuous-Current Mode(DCM) with valley detection. At mediumpower levels, it switches toFrequency-Reduction (FR) modeand limits the peak current to anadjustable minimum value. In low-power mode, the PFC switches off tomaintain high efficiency. The PFC-switchingscheme uses a patent-pending technique

controlled by the application’s true frequencyto eliminate valley hopping. The PFC turn-offdelay is adjustable, and an external PFCswitch-on/switch-off override is also provided.

At very low power levels, when the flybackswitching frequency drops below 24kHz, theflyback converter switches to burst mode.During the non-switching phase of burstmode, the internal IC supply current isminimised to further optimise efficiency. Valley

switching is used in all operating modes.These modes ensure highefficiency at low power and good

standby power performancewhile minimising audible

transformer noise. The deviceimplements a partial circuit power-

down during burst mode, whichenables equipment using this device

to meet European Union ErP lot 6requirements.

NXP’s PMEG: page 7NXP’s PMPB40SNA: page 12PARTNERWORKING


Integrated FET and PWM controller packagereduces component count

Fairchild Power Switch technology continues to save energy, reducecosts and increase reliability


High-temperature aluminium capacitors offerlong life

Vishay Intertechnology has announceda new series of surface-mountaluminium capacitors which combineshigh-temperature operationup to 150°C with very lowimpedance, high ripplecurrent and long useful life.

Fairchild Semiconductor has introduceda range of FPS™ Green Mode powerswitches that help designers to savespace and cost in the latest high-efficiency Switched-Mode PowerSupply (SMPS) designs.

The FSL1x series is a two-chip-one-packagedesign which combines an avalanche-tolerant650-800V SenseFET and a current-modePWM controller. It is intended to replacedesigns that use discrete MOSFET and PWMcontrollers. It offers the advantages of lowersystem costs and reduced component count,while offering comparable efficiency andreliability.

Additionally, the green-mode functionality ofthe PWM controller helps designers tominimise stand-by power consumption, anessential requirement for complying withtoday’s energy regulations.

Fairchild's vertical DMOS technology, whichis resistant to the destructive effect ofavalanche voltages, enables the FSL1x powerswitches to survive for a long time atbreakdown, making them superior to

competitors’ designs that use lateral DMOStechnology.

The devices also offer flexibility and reducedproduction costs: a single platform designproviding for multiple input voltages can beimplemented with the FSL1x series.

An internal soft-start circuit smoothlyincreases the output voltage to help preventtransformer saturation while reducing stress onthe secondary diode. In addition, burst-modeoperation minimises power dissipation instand-by mode.

The new 160 CLA series ofpolarised aluminium electrolyticcapacitors features a non-solid,self-healing electrolyte. Rated for auseful life of up to 2,000 hours at150°C, they provide high reliabilityin high-temperature automotiveand industrial applications. Theyalso carry the automotive AEC-Q200 qualification.

For enhanced performance, the 160 CLAdevices feature a very low maximumimpedance of 0.035Ω at 100kHz. Ripple currentis a high 1.35A.

Offering excellent processing flexibility, thenew capacitors meet the rigorous IPC/JEDECJ-STD-020 soldering guidelines for severereflow conditions. For vibration-proofperformance, the capacitors are offered infour-pin and six-pin versions.


APPLICATIONS• Consumer electronics• Home appliances

FEATURES• Frequency modulation for attenuating EMI• Overload protection • Over-voltage protection • Thermal shutdown • Abnormal over-current protection • Output short-circuit protection • Auto-restart mode



APPLICATIONS• Automotive power trains and chassis

electronics• Industrial drives and automation• Equipment for renewable energy• Switched-mode power supplies

FEATURES• Capacitance range at 100Hz:

100µF to 3,300µF• Rated voltage: 16-50V• Useful life at 40°C:

300,000-400,000 hours• 1,000 hours shelf life at 0 V, 150°C



Package 650V 700V 800V

MDIP-8L

FSL106HRFSL106MRFSL116HRFSL116LRFSL126HRFSL126MRFSL136HRFSL136MR

FSL156MRIN

FSL117MRINFSL137H –

TP-220F 6LFSL126MRTFSL136MRTFSL176MRT

– FSL128MRTFSL138MRT

VISHAY

The 160 CLA series is available in six casesizes, ranging from 12.5mm x 12.5mm x13mm to 18mm x 18mm x 21mm.

Fairchild’s FAN6224: page 2Fairchild’s FDB9403: page 7PARTNERWORKING



The PMPB40SNA is an N-channel MOSFETwith breakdown voltage of 60V and maximumon-state resistance of 43mΩ, at 25°C and a gate-source voltage of 10V, allowing energy-efficientoperation in switching and line-driving duties.

The DFN2020MD-6 package is an industryfirst, featuring 100% wettable and thereforesolderable side pads.

NXP SEMICONDUCTORS

High-voltage MOSFETs offer robust body-diode performance

SuperFET II standard and Easy-Drive variants provide freedom to optimise switching performance andsimplify circuit design


This makes soldering and inspection mucheasier and meets requirements for automotiveoptical solder inspection. In addition, thepackage features an exposed drain pad whichenhances thermal performance boostingmaximum power dissipation to 1.5W. With itsextremely small outline, the DFN2020MD-6 isaround 1/7th the size of the popular SO-8package. This allows designers to achievesignificant space savings while at the sametime delivering robust automotive-qualifiedperformance.

The PMPB40SNA is one of 80 recentlyreleased MOSFETs in leadless 2mm x 2mmsingle, dual and 1mm x 0.6mm single DFNpackages. The portfolio contains P-channeland N-channel types from 12V to 60V withvery low on-state resistance, and includesvariants offering special features such asintegrated ESD protection.

Offered in two product families, theSuperFET II and SuperFET II EasyDrive, these MOSFETs offer lowvalues for the important parameter ofstored energy in output capacitance(Eoss). This results in higher efficiencyat light-load conditions. The devicesalso offer best-in-class body-dioderobustness, a feature that helpsdesigners to achieve high system

reliability inresonant-converterapplications.

Using an advancedcharge-balancetechnology, the newSuperFET II MOSFETsfeature low on-resistance and a lowgate charge and, as aresult, support highlyefficient power-supplydesigns.

A number ofadditional features arealso integrated intothe devices to simplifycircuit design andreduce componentcount. These featuresinclude a gate resistorthat greatly reducesgate oscillation andimproves overallperformance.

APPLICATIONS• Relay drivers• High-speed line drivers• Low-side load switches• Switching circuits

FEATURES• 12.9A maximum drain current• Gate-source voltage range: ±20V• Junction-temperature range:

-55°C to 150°C



APPLICATIONS• Telecom AC/DC power supplies• Industrial SMPS • Server AC/DC power supplies

FEATURESSuperFET II MOSFET

• Fast switching speed to maximise systemefficiency

• High power density

SuperFET II MOSFET Easy-Drive• Easy to design and use• Optimised switching performance• Low EMI • Reliable operation in abnormal conditions



Package SuperFET II MOSFET SuperFET II MOSFET Easy Drive

TO-220-3L FCP190N60FCP380N60

FCP190N60EFCP380N60E

TO-220F-3LFCPF190N60FCPF380N60FCPF400N60

FCPF380N60E

TO-251-3L (IPAK)short-lead FCU900N60Z –

NXP Semiconductors has combinedTrench MOSFET technology with thecompact 2mm x 2mm DFN2020MD-6(SOT1220) package to create thePMPB40SNA AEC-Q101 qualifiedMOSFET, allowing automotiveelectronics to become smaller, moreenergy efficient and cost effective.

Automotive MOSFETs deliver rugged performance ininnovative miniature package

Fairchild Semiconductor has introducedthe 600V N-channel SuperFET® IIMOSFET series of devices that offer theadvantages of a low board-spacerequirement and high reliability.

NXP’s PMEG: page 7NXP’s TEA1755: page 10PARTNERWORKING

D E S I G N N O T E



This Design Note by Freescale and Intersil discusses a referencedesign for measuring the output of precision sensors,combining Intersil’s Precision & Power Products applicationboard and the Freescale Kinetis L series microcontroller withARM® Cortex™-M0+ core.

Creating technological solutions to challenges such as how to managedwindling resources, increase productivity and improve quality of lifedepends heavily on extracting dependable data from sensors thattypically generate signals of very low amplitude and often operate underless than ideal conditions. Conditions often include high levels of electricalnoise and low supply voltages from a single cell or small battery.

Designing a suitable signal-conditioning network can demandconsiderable time and specialist analogue design skills. Offering a ready-to-use alternative, the Intersil and Freescale thermocouple and straingauge reference design uses the Intersil Precision & Power Productsapplication board as a complete analogue signal chain connecteddirectly to the well known Freescale Freedom FRDM-KL25Zdevelopment board. This board contains a MKL25Z128VLK4 Kinetis Lseries microcontroller with 128kbyte Flash and 16kbyte SRAM, andprovides features such as a capacitive touch-sense slider, accelerometer,tri-colour LED, and a P&E Multilink interface providing run-controldebugging and compatibility with various IDE tool chains.

This reference design illustrates precision temperature sensing using athermocouple and pressure measurement using a strain gauge. TheIntersil board provides the complete analogue signal chain for high-accuracy thermocouple and strain gauge measurements, comprising allnecessary precision ADCs, amplifiers and voltage references. Powercomponents on the Intersil board also generate all supply-voltage railsfor the application, operating from 5V supplied via the FreescaleFreedom board’s USB connection to the host PC.

The thermocouple design uses a K-type thermocouple with cold-junction compensation. As shown in Figure 1, this design uses Intersil’sISL28134 zero-drift amplifier, ISL21090 voltage reference, ISL22317Digitally-Controlled Potentiometer (DCP) and ISL26102 integrated low-noise Programmable-Gain Amplifier (PGA) and 24-bit Delta-Sigma ADC.The ADC features a 3rd-order modulator providing up to 21.5-bits ofnoise-free performance, with user-selectable word rates. The PGAprovides gains ranging from 1 to 128, which supports a full-scale rangeof ±19.5mV from a 5V reference.

The ISL26102 has high input impedance allowing direct connection ofsensors such as load-cell bridges to achieve the specified measurementaccuracy without additional circuitry. In the thermocouple section of theIntersil and Freescale reference design, the ISL26102 output isconnected to the Freescale MKL25Z128VLK4 microcontroller data bus.

The strain-gauge design is a bridge solution that is able to extract asmall sensor signal from a high-voltage common-mode signal of 10V orhigher. The design, as shown in Figure 2, uses Intersil’s ISL28617 40Vinstrumentation amplifier, ISL21090 low-noise precision voltage referenceand, again, the ISL26102 24-bit delta-sigma ADC connected to theFreescale microcontroller for data acquisition and processing of themeasured data. The design makes use of the microcontroller’s on-boardUSB ports to present the measured data on a display or other type ofHuman-Machine Interface (HMI).

The main power input is taken from the mini-USB connection on theFreescale FRDM-KL25Z Freedom board. This 5V supply provides thesource for generating the required +12V, +10V, and ±5V supplies for thedemo. It is first converted down to a clean, regulated 3.3V supply usingthe ISL80101 high-performance LDO on the Intersil precision and powerboard. The +12V rail is generated from this 3.3V supply using theISL97516 step-up regulator. The other voltages are generated by anICL7660 charge pump and an ISL80138 linear regulator.

The thermocouple temperature or applied strain can be monitoredusing the Graphical User Interface (GUI) of the PC-based applicationcontrolling the reference design via the mini-USB cable. The display willshow real-time data as either a numerical or graphical representation ofthe temperature or strain measurement.

Both sensor designs perfectly complement Freescale’s 32-bit Kinetis Lseries microcontrollers, which combine exceptional energy efficiency andease-of-use derived from the ARM Cortex-M0+ processor with theversatile connectivity, rich peripheral features, scalability and powerfulenablement ecosystem that are all part of the Kinetis 32-bit portfolio.The Kinetis L series frees power-critical designs from the limitations of 8- and 16-bit microcontroller architectures by combining low dynamiccurrent, low power consumption in stop modes, superior processingperformance, a broad selection of on-chip Flash memory densities andextensive analogue, connectivity and HMI peripheral options.

Intersil’s ISL26102 and ISL 26104devices are featured on page 15.

FREESCALE AND INTERSIL

The Intersil and Freescalethermocouple and strain-gauge

reference design

Fig. 2: Simplified strain-gauge schematic

Fig. 1: Simplified thermocouple schematic

Precision measurement meets 32-bit data-processing performance


Analogue and SensingIntegration is the theme that emerges most strongly from theselection of analogue and sensor components featured in thisApplication Spotlight. Across a variety ofparts, manufacturers have found cleverand useful ways to combine the basicanalogue or sensing element with adegree of on-chip or in-package signalconditioning or logic. The benefits this offers to the design

engineer range from the obvious reductionin component count and system size, tomore surprising benefits. Below, inMicrochip’s MCP19111 power-convertercontroller, for example, the basic controlloop is actually a conventional analoguetype. However, Microchip has built into thepackage an 8-bit PIC® microcontroller, andthis provides the designer with aconsiderable amount of flexibility in theway the converter circuit operates. For instance, the digitalelement controls the thresholds for the triggering of protection

functions, and the shape of the soft-start profile. As theseconfigurations are controlled by the MCU, they can easily be

programmed through an easy-to-usegraphical user interface in Microchip’s PICdevelopment tool. Elsewhere, integration has made

sensors easier to use. In Vishay’sVCNL3020 proximity sensor, on page 17,and the AS5048 position sensor fromams, on page 19, for instance, digitaloutputs provided over an I2C or serialperipheral interface can be handleddirectly by the application running on ahost microcontroller. In ON Semiconductor’s NOA3301, on

page 18, by contrast, integration is ananalogue phenomenon: one devicesenses both proximity and light. Here,integration enables the implementation in

a portable device of two functions, gesture recognition anddisplay backlight control, with a single chip.

Innovative hybrid power controller combines flexibility,speed and efficiency

The MCP19111 combines the best in analogue and digital power control, and can be used withMicrochip's expanded range of efficient power MOSFETs

Microchip has announced the world’sfirst digitally-enhanced analogue powercontroller for use in DC/DC converters.

The MCP19111 is a new hybrid type of power-management device. Operating across a widevoltage range of 4.5V to 32V, the MCP19111offers a marked increase in flexibility overconventional analogue-based controllers. The device supportsoutput voltages from 0.5Vto 3.6V.

It consists of ananalogue-based PWMcontroller and a fullyfunctional Flash-based,8-bit PIC® microcontroller.Like an analogue-onlycontroller, it offers highefficiency and fasttransient response. Whencombined with MOSFETswith a low figure of merit,the MCP19111 cancontrol DC/DC convertersachieving efficiency ofmore than 96%.

frequency can also be configured in a rangebetween 100kHz and 1.6MHz.

At the same time, Microchip has announcedthe expansion of its high-speed MOSFETfamily, introducing the MCP87018,MCP87030, MCP87090 and MCP87130.Rated at 25V, these 1.8mΩ, 3mΩ, 9mΩ and13mΩ logic-level MOSFETs are intended foruse in switched-mode power supplies. Allfeature a low figure of merit.

MICROCHIPBy adding an on-chip digital controller,Microchip has also been able to offercommunications interfaces and configurabilitynot available on analogue-only devices. Afterinitial device configuration using Microchip’sMPLAB® X development software, the PMBusor I2C interfaces can be used by a host tocommunicate with, or modify, the operation ofthe MCP19111. Configuration options includeanalogue compensation, MOSFET dead time,soft-start profile, over-current limit and over-and under-voltage limits. The switching

A P P L I C AT I O N S P O T L I G H T – A N A L O G U E A N D S E N S I N G

14 F R E E D E V E L O P M E N T K I T S AT W WW . M Y- B O A R D C L U B . C O M

APPLICATIONS• Switched-mode power supplies

FEATURESMCP19111

• 10mA maximum quiescent current• Analogue peak current-mode control• Integrated synchronous high- and low-

side MOSFET drivers• Integrated current sense• Minimal external components needed




DETAILSON PAGE

19



Rugged magnetic position sensor requires no PCBMELEXIS

The new MLX90364 from Melexis is acomplete Triaxis® linear and angularposition sensor package that requiresno PCB when mounted in automotivesensing modules.

The MLX90364 is qualified to the AEC-Q100and -Q200 automotive standards. It haspassed extreme robustness tests, such aslong exposures to ambient temperatures of upto 170°C.

Intersil's ISL26102/4 ADCs deliver outstanding noise-free performance andextensive configurability

The ISL26102 and ISL26104provide two-channel and four-channel differential multiplexedinputs, respectively, and deliverbest-in-class noise performanceat user-selectable conversionrates ranging from 2.5samples/s to a maximum of4,000 samples/s.

In precision instrumentation,these devices digitise smallsignals from low-cost sensorsaccurately, without the addedcost and complexity ofexternal amplifiers and signal-conditioning circuits.

INTERSIL

Intersil ISL26102 and ISL26104 24-bitADCs integrate an ultra low-noiseProgrammable-Gain Amplifier (PGA)featuring a wide gain range. It can beconnected directly to many types ofsensors such as load cells orthermocouples with a wide variety ofsensitivities.

The devices have low power consumption,dissipating just 50mW during conversions andalso implementing a 1µA shutdown mode.There is also a low-side power switch thatallows users to shut-down current to poweredsensors such as load cells.

The on-chip PGA provides gains ranging from1 to 128, allowing a full-scale range of±19.5mV from a 5V reference. The high inputimpedance allows direct connection of sensorssuch as load-cell bridges to ensure thespecified measurement accuracy withoutadditional circuitry. The delta-sigma ADCfeatures a 3rd-order modulator providing up to21.5-bit noise-free performance, at 10samples/s, and allows user-selectable wordrates. The converter can be operated from anexternal clock source, an external crystal, orthe on-chip oscillator.

APPLICATIONS• Weighing systems• Temperature monitoring and control• Load-safety systems• Industrial process control• Pressure sensors

FEATURES• Noise figure of 7nV/√Hz @ PGA gain = 128• Linearity error: 0.0002% of full-scale• 5V analogue supply voltage• Digital supply-voltage range: 2.7V to 5V• SPI connection to host controller• 7.5kV HBM ESD rating



APPLICATIONS• Absolute rotary-position sensor• Absolute linear-position sensor• Automotive systems

FEATURES• Selectable output modes:

analogue (ratiometric) or PWM• Open/short diagnostics• Over-voltage protection• Under-voltage detection• 48-bit identification number option• Operating temperature range:

-40°C to 150°C



The device uses a dual-mould packageconstruction, integrating the 12-bit position-sensing die also found in Melexis’ MLX90365with the decouplingcapacitors necessaryto meet thestringent ESDand EMCrequirementsof automotiveapplications.The sensor, whichsenses displacement in allthree axes, can be used tomeasure either linear or rotary position.

Once encapsulated, this package can bewelded or soldered directly to a ruggedconnector or termination and potted or over-moulded. The MLX90364’s dual-mouldpackage therefore makes a conventional PCB

arrangement redundant. Since PCBassemblies are vulnerable to failure whenexposed to vibration or extreme hightemperatures, automotive manufacturers canachieve higher reliability by implementingcontactless position sensing with theMLX90364.

Compared to a conventional sensor modulewith a discrete sensor IC, a design using theMLX90364 uses fewer components andcontains one-third the number of solder joints.

The magnetic angular information iscompensated by the device itself for variationsin magnetic-flux density. This feature providesbetter stability and accuracy of measurementover changes in temperature than is availablefrom conventional linear Hall sensors.

Low-noise ADCs save external components, support high-accuracy sensing



Ambient-light sensor integrates powermanagement, connects via I2C

The clear plastic package and feature-rich silicon of the BH1730FVC help to simplify system designs

ROHM SEMICONDUCTOR The device is housed in a clear moulded-plastic package and contains all the circuitryneeded to detect ambient-light intensity andcommunicate with the host system. Two PINphotodiodes, for visible-light and infrareddetection, minimise dependency on thecharacteristics of external light sources suchas sunlight or fluorescent, halogen or LEDlamps. The photodiodes each drive a separateamplifier and ADC connected to a logic blockgenerating digital results for the host. An

oscillator and Power-OnReset (POR) function arealso integrated on-chip.

The BH1730FVC’sinternal logic generates aninterrupt if the detectedlight level is outsidemaximum or minimumthresholds as programmedin internal registers. Theinterrupt signal is output toa dedicated externalInterrupt pin, which can beconnected to the hostcontroller, and is also usedinternally as part of thesensor’s built-in powermanagement.

In conjunction with the contents of internalregisters, which include a stop bit and one-time or continuous-operation selector, theinterrupt signal can be used to power-downthe device and thereby reduce system energyconsumption.

APPLICATIONS• LCD televisions• PC monitors• Portable game terminals• Digital still cameras and video cameras• Personal navigation devices• Medical devices

FEATURES• Sensitivity range: 0.008lx to 65535lx• High rejection of 50/60Hz light noise• ±15% measurement accuracy• Adjustable to compensate effect of optical

window• Current draw:

• 150µA active• 0.85µA power-down



APPLICATIONS• Machine-vision systems• 2D-barcode readers• Intelligent traffic systems• Motion monitoring• Security and surveillance equipment


The Rohm Semiconductor BH1730FVCis a fully integrated digital light sensorthat can be connected directly to thehost system via its built-in I2Cinterface, and provides value-addedfeatures such as a power-down modeand an Interrupt output.

New CMOS image sensors offer high dynamicrange and frame rates

Highly integrated VITA image processors cover a wide range ofresolutions and frame rates

ON Semiconductor has extended itsVITA family of configurable, flexible,easy-to-use CMOS image sensors.

VITA image sensors integrate an amplifier withprogrammable offset and gain for each channelof the industry-standard LVDS outputs. Higherframe rates are achieved with multiple regions ofinterest or sub-sampled read-out modes, whichare programmable over a serial peripheralinterface.

ON SEMICONDUCTORAn on-board sequencer generates all internaltiming for exposures and read-outs. Thesensors allow the setting of multiple slopes forextended optical dynamic range, called theHigh Dynamic Range (HDR) mode. Thismaintains good contrast in shadowed regionsof an image without saturating bright areas.

The VITA sensors also feature a 10-bit on-chip ADC and on-chip timing control tosimplify application development. They can beoperated in a low-noise rolling-shutter mode.In rolling-shutter mode, the sensor supports acorrelated double-sampling readout, reducingnoise and increasing the dynamic range.

Features VITA 1300 VITA 2000 VITA 5000 VITA 25K

Part Number NOIV1SE1300A-xxx NOIV1SE2000A-xxx NOIV1SE5000A-xxx NOIV1SE025KA-xxx

Resolution 1280 x 1024 1920 x 1200 2592 x 2048 5120 x 5120

Optical Format ½ inch 2/3 inch 1 inch 35mm

Pixel Size 4.8µm x 4.8µm 4.8µm x 4.8µm 4.8µm x 4.8µm 4.5µm x 4.5µmFrame Rate atFull Resolution 150 frames/s 92 frames/s 75 frames/s ≤ 75 frames/s

Master Clock 62MHz 62MHz 62MHz 340MHz

Package LLC-48 LLC-52 LLC-68 PGA-355 my-ftm.com/130328FOR PARTS ANDLATEST PRICING



Rugged MEMS pressure sensor offers superior signal integrity

Additional benefits of the VCNL3020 include an interrupt function that helps simplifysoftware design

The VCNL3020 combines the IRemitter, photo-pin-diode, signal-processing IC, and 16-bit ADC ina small 4.85mm x 2.35mm x0.83mm surface-mount package.While other products only achieveobject detection up to 100mm, theVCNL3020’s LED drive current isprogrammable in 10mA steps from10mA to 200mA, therebypermitting a sensing range of upto 200mm. The integrated LEDdriver could also drive an externalLED, which allows the range to beextended to over a metre.

VISHAY

The Vishay VCNL3020 is a fullyintegrated proximity sensor that featuresprogrammable LED-drive currentallowing long object-detection distances,an interrupt function for waking the hostmicrocontroller, and 16-bit effectiveresolution boosting crosstalk immunitybetween the emitter and detector.

The sensor can also be used as an opticalswitch for computing and industrial devicesand displays.

An online calculator at:www.vishay.com//optoelectronics/opto-sensors-calculator allows customers toestimate the current this device will draw in thetarget application.

The VCNL3020 also has high ambient-lightimmunity, which is achieved by modulating theemitter signal.

The interrupt function enables the sensor towork independently until a programmablethreshold value occurs, causing the sensor towake-up the microcontroller. This helpscustomers to reduce their software effort, andlower power consumption by eliminatingpolling of communications between the sensorand microcontroller.

Using the VCNL3020 as a proximity sensorfor touch-screen locking allows designers tosave power in a variety of portable electronics.

MELEXIS

APPLICATIONS• Vacuum sensor• Fluid pressure sensor • Filter monitoring• Dispensing systems• White goods

FEATURES• Operating temperature range:

-40°C to 150°C• Automotive-qualified • Automotive diagnostic features • Back side exposed for high resistance to

common automotive media• Assembled in a robust, easy-to-seal

package



APPLICATIONS• GPS terminals• Data loggers• Industrial controls• Medical devices• Computing and telecom equipment

FEATURES• I2C-bus host-communication interface• Supply-voltage range: 2.5V to 3.6V• 1.5µA standby current• Surface-mount package



Integrated optical proximity sensor saves space and power,enhances flexibility

The MLX90809 combines a piezo-resistiveMEMS pressure sensor with a low-noiseanalogue front-end and 16-bit sigma-delta ADC. It measures relative pressureover a programmable span of up to 1 bar. The accuracy of theMLX90809 is rated at a maximum±1.5% of a full span.

The analogue signalchain integratedin the MLX90809provides thenecessaryamplification and offsetcompensation for theMEMS sensing element. Abuilt-in 16-bit microcontrollerhandles temperature compensation andsupplies the diagnostic mechanisms requiredfor safety-critical applications.

Since Melexis’ MEMS technology iscompatible with standard CMOS fabricationprocesses, the sensor and signal-conditioningcircuitry can be made on the same wafer. Thismonolithic device delivers important advantagesover non-integrated pressure sensors, in whichthe signal conditioning takes place severalmillimetres away from the sensing. These

include superior signal integrity andreduced susceptibility to EMI.

Featuring an on-board EEPROM, theMLX90809 allows the user to set

diagnostic functions such asover-voltage and under-voltagesupply conditions and over-

pressure or under-pressurelimits, as well asselectable digital-filtersettings to reduceoutput noise ordecrease responsetime.

The MLX90809sensor can transferpressure data asan analogueoutput voltageproportional to

the supply voltage,or using the SENT

digital protocol.

Melexis has introduced an integratedMEMS pressure sensor and signal-processing chip, providing accuratemeasurements under harsh automotiveoperating conditions.

Non-contact sensing using the AH18xx series allows numerous appliances and controlsto deliver enhanced user experiences

Diodes Incorporated has extended itsbroad portfolio of Hall-effect switcheswith a variety of omnipolar devicesoffering low power consumption andsmall package size.

The AH18xx devices are suitable foruse in proximity- and position-detection applications, and canfunction as contactless switches ina wide variety of consumer andindustrial products.

The high-sensitivity AH1806 andAH1808 have been optimised forbattery-powered equipment,typically consuming just 24µW on a3V supply. With operatingthresholds at ±30G and ±40G,these SOT553-packaged switchesenable close control of the detectionpoint.

Used with stronger magneticfields, the medium-sensitivityAH1807 and low-sensitivity AH1809provide typical operating points of

DIODES INCORPORATED



Combined proximity and ambient-light sensor helpsimprove mobile-device displays

The innovative NOA3301 allows portable devices to become evensmarter through enhanced context awareness

ON Semiconductor’s NOA3301combines a proximity sensor andambient-light sensor in a single chip,simplifying the design of backlightcontrol and gesture-recognition systems.

ON SEMICONDUCTOR

±80G and ±130G respectively. For addedflexibility, the input supply range of thesedevices is 2.5-5.5V. The extended operatingtemperature ranges from -40ºC to 125ºC.There are two package options: SOT553 andSIP-3L. These two devices, as well as theAH1806 and AH1808, will also be available inan SC-59 package by the middle of 2013.

The world’s smallest programmableomnipolar Hall effect switch, the AH1892, isideal for space-constrained products. In theminiature four-pin 0.7mm x 0.7mm x 0.5mm

U-WLB0707-4 package, the micropowerAH1892 is 17 times smaller than common 3-pin TSOT-packaged alternatives.

With a lower operating voltage range of 1.6Vto 3.6V, and drawing an average current of just4.3µA, the switch ensures battery life isprolonged. Sensitivity can also be adjusted onthe fly via an external logic source.

The NOA3301 combines an advanced digitalproximity sensor and infrared-LED driver withan Ambient-Light Sensor (ALS) and I2Cinterface with interrupt capability in anintegrated monolithic device. Featuring variouspower-management controls and very lowactive-sensing power consumption, theNOA3301 is ideally suited to use in battery-operated and mobile devices.

The proximity sensor measures reflectedlight intensity with a high degree of precisionand excellent ambient-light rejection. TheNOA3301 supports the design of a proximity-sensor system with a 32:1 programmable LEDdrive-current range and a 30dB overallproximity-detection threshold range.

At the same time, the device’s ALS offersphotopic light response, dark-currentcompensation and high sensitivity. This meansthat its accurate response to changes inambient light mirrors that of the human eye,even in the presence of dark cover glass.

The NOA3301 therefore enables designersto improve the user experience byenhancing the screen interface, both bymeasuring distance and sensing gestures inreal time, and by changing the intensity of thedisplay backlight in response to changes inambient light.

APPLICATIONS• Portable electronics• Home appliances• Smart meters• Security systems

FEATURES• Low-power operation• Wide range of sensitivity options• Compact low-profile packaging• High stability and reliability



APPLICATIONS• Mobile internet devices• MP3 players• GPS navigation systems• Backlit keypads

FEATURES• Output counts proportional to ambient-

light intensity• Operates in sunlight and artificial light• High dynamic range



Hall switches optimise detection circuits

Implementing both functions in the same device simplifies designand enhances reliability

Board of the Month

The new AS5048 Eval Kit from ams providesfor the attachment of an AS5048 magneticrotary position sensor to a variety of standard-size stepper motors, enabling the easy andfast evaluation of the sensor in a realapplication.

The Eval Kit includes an adaptor PCB towhich the AS5048 is soldered, four magnetholders sized to fit various shaft diameters,and an Allen key to fix the magnet holder tothe shaft.

Two variants of the Eval Kit are available: theAS5048A Eval Kit is configured for a SerialPeripheral Interface (SPI) and the AS5048BEval Kit is configured for an I2C interface. Bothalso provide a PWM output signal.

The AS5048 IC is a 14-bit magnetic rotaryposition sensor for absolute angle positionsensing, measuring at a resolution of 16,384positions in a full 360° turn.

Future Electronics’ Board Club: supporting innovative electronics designEurope’s electronics industry thrives on the application of innovation and creativity, and anessential innovator’s tool in design projects is the development board. The Board Club website is aFuture Electronics resource for users of development boards. Here, and only here, Board Clubmembers can gain access to exclusive free development boards and development board offers.If you would like to register for membership, please visit: www.my-boardclub.com/register.php

To apply for these free boards go to: www.my-boardclub.com/ftmTerms and conditions apply. Visit www.my-boardclub.com/about_us for details

D E V E L O P M E N T B O A R D S I N T H I S I S S U E

19

Kit enables evaluation of magnetic positionsensing on a real stepper motor


The sensor’s zero position can be programmedinto the IC after assembly via a simple SPI orI2C command, which eliminates the need for aspecial programmer. This feature makes theAS5048 easy to implement in microcontroller-based designs for rotary position sensing.

The AS5048 is highly tolerant ofmisalignment between the sensor IC and itspaired magnet and of variations in the air gap,at typically 2mm, ±50%. It operates intemperatures ranging from -40°C to 150°C.

Evaluation kit references:AS5048A-EK-AB-STM1.0AS5048B-EK-AB-STM1.0

my-boardclub.com classifiedsFreescaleAutomotive-MCU prototyping

Rapid prototyping and microcontrollerevaluation for important automotive-microcontroller families with its emergingseries of StarterTRAK USB developmentsystems that provide everything neededto test-drive the microcontroller in acompact, USB-pluggable unit.

Board References:TRK-MPC5606BTRK-USB-MPC5643L TRK-USB-S12G

Response Number: 10

FreescalePROFIBUS reference platform

Accelerating development of electroniccontrol systems, safety systems andM2M devices for remote control andmonitoring in industrial automation.

Board References:TWR-P1025 Tower System moduleTWR-IND-IO connectivity module

Response Number: 18

International Rectifier35W/4 x 2-channel Class-D audiopower amplifier using the IR4311

The IRAUDAMP15 reference design is a2-channel, 35W/ch half-bridge Class-Daudio power amplifier with single powersupply. This reference design demonstrateshow to use the IR4311 IC with singlepower supply, implement protection circuits,and design an optimum PCB layout usingPowIRaudio integrated Class-D IC.The IRAUDAMP18 is for evaluating theIR4312 device.

Board Reference:IRAUDAMP15IRAUDAMP18

Response Number: 06

MicrochipPower management

The MCP19111 evaluation board isoffered with standard firmware, which isuser-configurable through an MPLAB® XIDE plug-in. It includes high-speedMOSFETs from Microchip.

Board Reference:ADM00397

Response Number: 24

By Michael RoederField Applications Engineer, Future Electronics (Germany)

T E C H N I C A L V I E W

GNU/Linux was originally an Operating System (OS) fordesktop computers and servers, in which the determinism ofoperations is not a critical feature. But GNU/Linux alsoappeals strongly to embedded system designers, and themission-critical requirements of some embedded systemshave prompted various efforts to modify or extend Linux inorder to provide time determinism and real-time capabilities.

Some solutions are proprietary, supplied by commercial enterprises, butthis article provides an insight into the three open-source GNU/Linuxreal-time extensions currently available to embedded designers.

Of course, when real-time is examined, it is important to be clearabout what is meant by ‘real-time’. In a hard real-time environment, asystem will always meet its deadlines. This means that the system hasto guarantee:• strict event determinism• bounded latencies; in other words, it must offer a guaranteed worst-

case latency

Hard real-time operation is usually required in safety- or system-criticalapplications in, for example the automotive, avionics, medical andautomation sectors.

A soft real-time environment is usually optimised for a best-effortoutput. In most cases, real-time criteria will be met, but there is noguarantee. Common applications include audio and video encoding andbroadcast, and VoIP.

A concept linked to that of real time is pre-emption: the ability of asystem to interrupt tasks at many pre-emption points, as shown inFigure 1. The longer the non-interruptible programme units are, thelonger is the waiting time (latency) of a higher priority task before it canbe started or resumed. GNU/Linux is user-space pre-emptible: it allowsuser tasks to be interrupted at any point. The job of real-time extensionsis to make system calls also pre-emptible.

In its current form, GNU/Linux can at best satisfy soft real-timeconditions as it is not, by design, a hard RTOS. At the same time, plentyof commercial RTOS are available for those with real-time requirements.So why would an engineer bother to modify GNU/Linux to meet RTOSrequirements?

The reasons are usually similar to the reasons that Linux has been asuccess in desktop and enterprise computing:• Open architecture, open-source licences and no software patents• Wide choice of application software, available in source code• Total code transparency• Support for a wide range of processors and other hardware• Support for the latest technology in domains such as wireless

communications, internet protocol and security • Community support • Lower total cost of ownership compared to a commercial RTOS

Today, there are three mainstream open-source choices forimplementing real-time applications with GNU/Linux: • Linux with the RT_PREEMPT patch (Linux/PREEMPT_RT)• RTAI • Xenomai

The PREEMPT_RT project is a set of patches for standard Linux kernels,aimed at improving the native real-time capabilities of GNU/Linux. Theproject’s goal is to get all its patches approved for addition to themainline kernel and, for many, this has already been achieved.

RTAI uses a dual-kernel system: a small deterministic real-time kernelwith scheduler, and the regular Linux kernel. The Linux kernel is modified

to access an interrupt abstraction layer, theRTHAL, instead of the hardware directly.This allows the real-time kernel to block theLinux kernel while executing real-timefunctions.

Xenomai was launched in 2001 with theaim of not only providing real-timecapabilities to GNU/Linux, but also ofmaking it easier to port software written forother RTOS to GNU/Linux. To achieve this,it provides real-time APIs for POSIX*1003.1b, VxWorks, pSOS+, VRTX, uITRONand RTAI. Known as skins, these can beused to easily port applications written forthose operating systems to GNU/Linux.

Of the three products, Xenomai hastechnical features which, in this author’sopinion, make it the most interesting freehard real-time extension to GNU/Linux.

Real-time Linux for embe source the right choice?

READ THIS TO FIND OUT ABOUT

• The limitations of the Linux OS in real-time embedded applications• The choice of open-source Linux extensions that provide real-time

performance• How Xenomai provides designers with a flexible means to

implement real-time applications on Linux

Fig. 1: The operation of non-pre-emptive (left) and pre-emptive (right) operating systems





dded processors: is open

Originally, Xenomai was solely based on a dual-kernel concept usingthe Adaptive Domain Environment for Operating Systems (ADEOS) I-Pipe as an interrupt abstraction layer. In this case, Xenomai providesthe real-time kernel, and the Linux kernel is just a special low-prioritytask which can be interrupted at any time; it is quite similar to the RTAIapproach.

The forthcoming Xenomai 3.0, however, can operate as a POSIX userthread on any regular Linux kernel, usually with PREEMPT_RT enabled.It therefore allows all applications implemented on Xenomai skins to rundirectly on a monolithic kernel. In other words, Xenomai 3.0 acts as anabstraction layer over the regular Linux kernel, providing this kernel’sreal-time capabilities to its applications through the various skins.Xenomai 3.0 only requires the standard POSIX API, so that no patchingor porting to particular kernel versions is needed.

This gives the developer of applications for Xenomai a useful choice:to run the applications under a small, lightweight and industry-provenreal-time kernel, or under a pre-emptible Linux monolithic kernel. It isimportant to understand, however, that the second choice means that allreal-time capabilities have to come from, and are only as good as, theunderlying Linux kernel itself.

Dual kernel versus native pre-emptionEach method has its own benefits. The co-kernel approach has theadvantage that the real-time application is totally independent of theLinux kernel and only depends on the real-time kernel, scheduler andabstraction layers. There is a clear separation between the real-time andnon-real-time domain. This simplifies maintenance, timing and safetycertification.

Porting to new CPU architectures is also easy, because only theabstraction layers have to be adapted. An interrupt abstraction layerpatch, however, is always specific to a certain kernel version, andpatches are only available for selected versions of the mainline kernel.

Under the single-kernel approach with the Linux/PREEMPT_RT patch,a POSIX real-time API allows real-time applications to be developed inthe GNU/Linux user-space, and to benefit from all development,debugging and profiling tools available there.

At some point in the future, the RT_PREEMPT patch will becompletely merged into the mainline kernel, and then it will be simple tocompile a real-time kernel for any supported system. Then, however,every modification to the operating system, such as kernel patches ornew drivers, might influence the system in a potentially undesirable way.Therefore the system will have to be re-qualified and possibly re-certifiedafter such modifications.

Another drawback is that the Linux/PREEMPT_RT patch entails higherworst-case latencies than a dual-kernel system.

In the author’s opinion, using the POSIX real-time API is the bestanswer to the problem of deciding between the two approaches.Depending on the specific requirements of the end-product, POSIX real-time applications can either run on Xenomai’s dedicated real-time kernelor on a single Linux/PREEMPT_RT kernel.

Performance evaluation in the real worldSo just how real is the real-time performance of Linux? Below is amethod to get a quick first impression of the latency of any givensystem. The cyclictest tool is used to schedule a task with the highestpriority every 10ms. The tool knows when this task is expected to runand calculates the latency or deviation from this expected time.

Table 1 shows the results of a test run on a Freescale i.MX53 ARM®

Cortex™-A8 processor operating at 1GHz. It ran Linux kernel 2.6.38 fromthe DENX Linux tree. Two different test systems were set up.

S_CPRE: standard kernel with CONFIG_PREEMPT pre-emptible kernel(Low-Latency Desktop) enabled../cyclictest –m -n -p99 -t1 -i10000 -1360000

S_XENO: Kernel + Xenomai 2.6.0-rc4 + I-Pipe 1.18-03./cyclictest -n -p99 -t1 -i10000 -1360000

The average latency shows the typical values that can be expected fromthis system. For developers of hard real-time applications, however, onlythe maximum latency is of interest. The table clearly shows the superiorperformance of a dual-kernel system.

Conclusion When the entire PREEMPT_RT patch has gone into mainline Linux, it willbe the method of choice for ordinary real-time applications. Xenomai 3.0will then allow easy porting of existing applications to a single, real-timeLinux kernel. A dual-kernel approach will continue to be mostappropriate for hard real-time requirements.

For developers of new applications, the use of the POSIX API is highlyrecommended whether they are implementing a single- or dual-kernelsystem.

In the near future, the trend to use multi-core processors will allow fornew solutions to the problems discussed in this article. For example, it isalready possible in mainline GNU/Linux to assign interrupts to a CPUcore and to keep non-real-time tasks away from this core. Interestingly,therefore, a multi-core system nullifies the performance advantage of thedual-kernel approach. An asymmetric CPU such as Freescale’s Vybridprocessor family, using a combination of ARM Cortex-A5 and Cortex-M4cores, offers the option of running multiple operating systems, eachoptimised for different functions, to achieve an even greater improvementin the system’s hard or soft real-time performance.

* POSIX is a series of IEEE standards that help to ensure compatibilityacross operating systems by defining a series of Application ProgrammeInterfaces (APIs), functions and command-line shells for use by the OS.Many embedded OS are POSIX-compliant, including VxWorks®, Linux®,MQX® and QNX®.

Table 1: Cyclic test of single- and dual-kernel Linux systems

Latency/µsSystem S_XENO S_CPRE

First RunS_CPRE

SEcond Run

Minimum 2 27 13

Average 43 88 81

Maximum 58 415 1829

READ THIS TO FIND OUT ABOUT

• The advantages of using an RTOS in embedded-system design• Key criteria for selecting an open-source RTOS• How wider factors such as middleware, support, licensing and

project-engineering resources influence selection



How to choose the right fre

This article explains the advantages a Real-Time OperatingSystem (RTOS) can offer embedded-system developers, anddiscusses how to choose the most suitable RTOS from themany options currently available.

RTOS benefitsAn RTOS and its accompanying toolbox provide valuable features andservices that can help developers to overcome technical challenges,simplify development and shorten time to market. The RTOS provides aframework on which to build and organise the features of a system. Itsdeterministic response can facilitate ensuring that a given set of tasks allmeet their deadlines. Tasks only run when events occur, which savespolling, and tasks waiting for events do not consume CPU cycles. AnRTOS can also help to avoid problems that can occur in applicationcode, by providing multitasking capability and allowing the application tobe broken down into smaller pieces.

The toolbox that accompanies the RTOS also provides valuableservices such as inter-task communication and time management. Evenfor systems that have no need of real-time capability, the code can beclearer and better organised if based on an RTOS, partly because itpromotes code reuse.

Making the choiceMost programmers are not familiar with RTOS constraints andrequirements, and will usually make a decision based either on theRTOS performance or on familiarity with the product. The wide variety ofoptions available, including commercial and open-source offerings bysuppliers ranging from software specialists to processor vendors,warrant greater care in the selection process.

An RTOS should be seen as just one component of a completedevelopment ecosystem, which includes the development tools suite,comprising C/C++ compiler, debugger and optional state-machineverification, other middleware such as communications stacks, and theprocessor itself. This means that the developer must consider not onlywhich is the ideal RTOS for the application, but also which best suits thetarget microcontroller, and which development tools will make it simpleto incorporate the RTOS and selected middleware. Additionally, for amore complex application, it will be necessary to consider the bestdebugging methodology when running under an RTOS. Choosing a pre-integrated solution, with development tools optimised for both themicrocontroller and the RTOS, and with dedicated middleware, canprovide a new user with an easier route than buying the individualcomponents from different vendors.

The order in which tasks are performed, and their timing, are bothdetermined by the scheduler or dispatcher. There are two types ofscheduler: non pre-emptive and pre-emptive. Pre-emptive scheduling isthe more sophisticated approach: when an event or Interrupt-ServiceRoutine (ISR) makes a higher priority task ready-to-run, the current taskis immediately suspended and the higher priority task is given control ofthe CPU. Most real-time systems use pre-emptive schedulers becausethey are more responsive than non pre-emptive kernels.

Wider selection criteriaIn addition to considering the properties of the RTOS itself, thedeveloper should also evaluate the needs of the project. It is necessaryto identify the individual components that will be required, such as buildtools and communication stacks. It is usually best to source a completepackage, including the RTOS, rather than buying bits and pieces.

Evaluation is made much easier if a starter kit (STK), an IntegratedDevelopment Environment (IDE) and debug task-aware tools are used. Itis worth beginning with sample projects and Board-Support Packages(BSPs) supplied with the product for the specific target device. RTOSsupport provision can also be tested out at this stage. Subsequently,implementation is also best achieved by starting with the sampleprojects and BSP supplied.

The BSP should provide all the hardware-specific drivers and routinesthat are needed to run the application on the target hardware. Task-oriented design can then take place.

RTOS (kernel) awareness can be a great help while debugging theapplication, and with a zero-compile-time configuration, the system isconfigurable only at run-time. A high-performance compiler should alsoinclude a MISRA C checker. Originally developed by the Motor IndustrySoftware Reliability Association (MISRA), MISRA C is a software-development standard that is now widely used throughout the industrialand medical sectors.

e RTOS for your applicationT E C H N I C A L V I E W


Factors that should be considered inchoosing an open-source RTOS include:

ScalabilitySize or memory footprint is an importantconsideration. Most RTOS are scalable inthe sense that only the code required isincluded in the final memory footprint.Looking for granular scalability in an RTOSis a worthwhile endeavour, as it minimisesmemory usage.

PortabilityOften, a current application may outgrowthe hardware it was originally designed foras demands placed on the end-productincrease. A suitable RTOS can therefore beported between processor architectures

and between specific target systems. A standard ApplicationProgramming Interface (API), like POSIX, is also a major benefit toportability.

Run-time facilitiesRun-time facilities refer to the services of the kernel, which typicallyinclude inter-task communication, task synchronisation, interrupts andevents handling, and more. Different application systems have differentsets of requirements. Comparisons between systems frequently centrearound these kernel-level facilities.

Run-time performanceRun-time performance of an RTOS is generally governed by the interruptlatency, context-switching time and a small number of other kernel-performance metrics. These are often useful considerations ifperformance-critical aspects of the application are to be prototyped onstandard hardware to assess the performance. For embedded systems,of course, code density can also be important.

Completeness/middlewareOther very important factors that should be considered include theRTOS demands on available system power and resources, as well as


availability of communications stacks such as TCP/IP or USB,middleware, and other package tools such as a file system and Flashfile-systems converter. For graphic-rich HMI-based projects, theavailability of high- quality rendering software and libraries can make orbreak a design.

Development toolsAn adequate set of development tools including debugger, compiler andperformance profiler might help in shortening the development anddebugging time, and improve the reliability of the code. The more tightlythese are coupled to the RTOS the easier the development route will be.A comprehensive suite of starter kits and advanced development kitsshould be available for the chosen microcontroller architecture to provideeverything the developer needs to get started straight out of the box.

Licensing and financial factorsIt is also important to assess the total cost of ownership, including anypayment model such as licence fee or royalties and any maintenancesubscription that may be incurred. In some cases it can be tempting tochoose a ‘free’ RTOS, but this may not deliver the lowest total cost ofownership in the longer run. The engineer should look carefully atavailable in-house skills, and the time available for the project, beforecommitting to a system that relies on other users for support.

Future-proofingDevelopment with an RTOS is not a problem-free process. Reliabilityand consistent support from a supplier is a critical factor in ensuring theprompt completion of a project. This is something that may beoverlooked if opting for an open-source RTOS: although the licence feecan be saved, the total cost may be high if the developer must devotesignificant learning time, or if consultants must be employed to ensuresuccessful completion. Table 1 lists important attributes of some popularopen-source RTOS.

ConclusionAlthough using an RTOS for the first time can seem like a major step,the right choice of RTOS can simplify getting started. With a pre-integrated solution, familiar tools, an intuitive starter kit and the right levelof high-quality technical support, it is possible for an RTOS beginner tocomplete a system design successfully within an acceptable time.

Table 1: Comparison of open-source RTOS

RTOS Scalability Current Version Development Tools Further Information

FreeRTOS Very good v7.1.0 IDE independent http://www.freertos.org/

eCos Good v3.0 eCos software configuration and build tools http://ecos.sourceware.org/

ChibiOS/RT Good v2.4.0 http://www.chibios.org

CooCox, CoOS Good v1.1.4

CooCox CoIDE

http://www.coocox.orgCooCox Colink

CooCox CoFlash

CooCox CoSmart

scmRTOS Very good v4.00 http://scmrtos.sourceforge.net

BeRTOS Good v2.7 http://www.bertos.org/

Freescale MQX™ Good v3.8.0IDE - CodeWarrior v10

http://www.freescale.comSTK - complete eval kits portfolio

future technology magazine · 2013-07-19 · future technology magazine issue 1303 design note:...

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